Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the
Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90
days. Yes x No ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every
Interactive Data File required to be submitted and posted pursuant to Rule 405 of regulations S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such
files). Yes x No ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See the
definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act.

Large accelerated filer

x

Accelerated filer

¨

Non-accelerated filer

¨ (Do not check if a smaller reporting company)

Smaller reporting company

¨

Indicate by check mark whether the registrant is a shell company (as defined in Exchange Act
Rule 12b-2). Yes ¨ No x

As of August 4, 2010, the number of shares outstanding of the registrants common stock, par value $.01 per share, was
39,822,711.

Explanatory Note

The purpose of this Amendment No. 1 to our Quarterly Report on Form 10-Q for the period ended June 30, 2010, as filed with the
Securities and Exchange Commission on August 6, 2010, is to furnish Exhibit 101 to the Form 10-Q as required by Rule 405 of Regulation S-T. Exhibit 101 to this report provides the following items from our Form 10-Q formatted in Extensible
Business Reporting Language (XBRL): (i) the unaudited Condensed Consolidated Statements of Income, (ii) the unaudited Condensed Consolidated Balance Sheets, (iii) the unaudited Condensed Consolidated Statements of Cash Flows, and
(iv) the notes to the unaudited condensed consolidated financial statements, tagged as blocks of text.

Users of this
data are advised that pursuant to Rule 406T of Regulation S-T these interactive data files are deemed not filed or part of a registration statement or prospectus for purposes of sections 11 or 12 of the Securities Act of 1933, are deemed not filed
for purposes of section 18 of the Securities and Exchange Act of 1934, and otherwise are not subject to liability under those sections. No other changes have been made to the Form 10-Q other than those described above. This Amendment
No. 1 does not reflect subsequent events occurring after the original filing date of the Form 10-Q or modify or update in any way disclosures made in the Form 10-Q.

Item 6.

The following exhibits
are filed herewith:

Exhibit

No.

Description

3.1

Restated Certificate of Incorporation of the Company (Incorporated herein by reference to Exhibit 3.2 to the Companys Registration Statement on Form S-1
(Registration No. 333-33447)).

3.2

Certificate of Designations of Series A Junior Participating Preferred Stock of the Company (Incorporated herein by reference to Exhibit 3.1 to the Companys report on Form 8-K
dated November 25, 2008).

3.3

Amended and Restated Bylaws of the Company (Incorporated herein by reference to Exhibit 3.1 to the Companys report on Form 8-K dated December 21, 2007.)

4.1

Form of certificate representing Common Stock (Incorporated herein by reference to Exhibit 4.2 to the Companys Registration Statement on Form S-1 (Registration No. 333-33447).

4.2

Registration Rights Agreement among the Company and certain stockholders (Incorporated herein by reference to Exhibit 4.2 to the Companys Registration Statement on Form S-1
(Registration No. 333-33447).

4.3

Rights Agreement dated as of November 24, 2008 between Dril-Quip, Inc. and Mellon Investor Services LLC, as Rights Agent (Incorporated herein by reference to Exhibit 4.1 to the
Companys Current Report on Form 8-K filed on November 25, 2008).